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• Multiple overlays using ffmpeg

  23 mars 2018, par lhan

  I’m trying to satisfy a few layering scenarios for building video files using ffmpeg.

  Scenario 1 : Overlay a video (specifying opacity of the video) on top of an image, creating a new video as the result.

  I solved this with :

  ffmpeg -i video.mp4 -i image.jpg -filter_complex '[0]format=rgba,colorchannelmixer=aa=0.7,scale=w=3840:h=2160[a];[1][a]overlay=0:0' -t 30 output.mp4

  I’m scaling the video to 3840x2160 to match my image (ideally I’d have them matching beforehand).

  Scenario 2 : 3 layers now, video - image - image. The middle image layer is a transparent image with text. So we have a base image, with text overlaid, and a video on top of that at a certain opacity.

  I solved this with :

  ffmpeg -i video.mp4 -i image.jpg -i text.png -filter_complex '[0]format=rgba,colorchannelmixer=aa=0.7,scale=w=3840:h=2160[a];[2][a]overlay=0:0,scale=w=3840:h=2160[b];[1][b]overlay=0:0' -t 30 output.mp4

  Scenario 3 (which I can’t get working) : Same as Scenario #2, but with text on top of the video.

  I tried re-arranging my filter, hoping to affect the layering order :

  ffmpeg -i video.mp4 -i image.jpg -i text.png -filter_complex '[2]overlay=0:0,scale=w=3840:h=2160[a];[0][a]format=rgba,colorchannelmixer=aa=0.7,scale=w=3840:h=2160[b];[1][b]overlay=0:0' -t 5 output.mp4

  But that gives the following error :

  Too many inputs specified for the "format" filter. Error initializing complex filters. Invalid argument

  Full Error :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from ’video.mp4’ :
  Metadata :
  major_brand : mp42
  minor_version : 0
  compatible_brands : mp42mp41
  creation_time : 2018-03-09T20:52:18.000000Z

  Duration : 00:00:30.00, start : 0.000000, bitrate : 8002 kb/s

  Stream #0:0(eng) : Video : h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 7997 kb/s, 24 fps,
  24 tbr, 24k tbn, 48 tbc (default)

  Metadata :
  creation_time : 2018-03-09T20:52:18.000000Z
  handler_name : Alias Data Handler
  encoder : AVC Coding Input #1, image2, from ’image.jpg’ :

  Duration : 00:00:00.04, start : 0.000000, bitrate : 526829 kb/s

  Stream #1:0 : Video : mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 3840x2160 [SAR 96:96 DAR 16:9], 25 tbr, 25 tbn, 25 tbc Input #2,
  png_pipe, from ’text.png’ : Duration : N/A, bitrate : N/A

  Stream #2:0 : Video : png, rgba(pc), 1500x1500, 25 tbr, 25 tbn, 25 tbc [AVFilterGraph @ 0x7fc37d402de0]

  Too many inputs specified for the "format" filter. Error initializing complex filters. Invalid argument

  I can sort of get around that by tweaking the command so that the text isn’t an input to the overlay :

  ffmpeg -i lightTexture.mp4 -i image.jpg -i textSample.png -filter_complex '[2]overlay=0:0,scale=w=3840:h=2160;[0]format=rgba,colorchannelmixer=aa=0.7,scale=w=3840:h=2160[b];[1][b]overlay=0:0' -t 5 output_text_on_top.mp4

  But then my output video is all messed up. I suspect I am on the wrong track by trying to cram all of this into the -filter_complex. I’m wondering if I need to create two overlays and then overlay those (i.e overlay Text onto the Video, and then overlay that onto the base image) though I’m not sure how to accomplish that.

  If anyone could point me in the right direction here, I’d be super grateful.

• Naive Sorenson Video 1 Encoder

  12 septembre 2010, par Multimedia Mike — General

  (Yes, the word is “naive” — or rather, “naïve” — not “native”. People always try to correct me when I use the word. Indeed, it should actually be written with 2 dots over the ‘i’ but who has a keyboard that can easily do that ?)

  At the most primitive level, programming a video encoder is about writing out a sequence of bits that the corresponding video decoder will understand. It’s sort of like creating a program — represented as a stream of opcodes — that will run on a given microprocessor or virtual machine. In fact, reading a video codec bitstream specification will reveal a lot of terminology along the lines of “transmitting information to the decoder” or “signaling the decoder to do xyz.”

  Creating a good encoder that will deliver decent quality at a reasonable bitrate is difficult. Creating a naive encoder that produces a technically compliant bitstream, not so much.

  
  
  

  When I wrote an FFmpeg encoder for Sorenson Video 1 (SVQ1), the first step was to just create a minimally compliant bitstream. The coarsest encoding mode that SVQ1 allows is to encode the average (mean) of each 16×16 block of samples. So I created an encoder that just encoded the mean of each block. Apple’s QuickTime Player was able to play the resulting video in all of its blocky glory. The result rather reminds me of the Super Nintendo’s mosaic effect.

  Level 5 blocks (mean-only 16×16 encoding) :
  

  
  
  

  Level 3 blocks (mean-only 8×8 encoding) :
  

  
  
  

  It’s one thing for your own decoder (in this case, FFmpeg’s own decoder) to be able to decode the data. The big test is whether the official decoder (in this case, Apple QuickTime Player) can decode the file.

  
  
  

  Now that’s a good feeling. After establishing that sort of baseline, it’s possible to adapt more and more features of the codec.

• Premium Plugins now available on the Piwik Analytics Marketplace

  2 novembre 2016, par Piwik Core Team — Community, Press Releases

  We are super excited to announce the launch of three new premium plugins which are now available on the Piwik Marketplace : A/B Testing, Media Analytics, and Activity Log.

  All three plugins are easy to use and come with 100% data ownership, documentation, integration with Piwik, powerful data exports and no data limits.

  These first premium plugins and the new Marketplace capabilities have been designed and built with love by InnoCraft – the new company brought to you by the makers of Piwik.

  1. A/B Testing

  A/B Testing helps you grow your business by comparing different versions of your website or app to detect the most successful version that increases your sales, revenue, conversions, pageviews, and more.

  A/B tests are also known as experiments or split tests. In an A/B test you show two or more different variations to your users (visitors) and the variation that performs better wins. When a user enters the experiment, a variation will be randomly chosen and the user will see this variation for all subsequent visits. Piwik A/B testing uses advanced statistical analysis to detect which variation performs better for your conversion goals and success metrics. Even small tests can increase your sales and conversions massively !

  Get it now on the Marketplace

  Learn more here :

  • A/B Testing – Experiments (website).
  • List of all features on the Marketplace : A/B Testing Plugin.

  • The A/B Testing User Guide and the A/B Testing FAQ help you getting started in running A/B tests. The A/B Testing developer guides help you embedding and implementing A/B tests into your project.

  • A/B Testing Platform for Piwik Analytics (blog post).

  

  2. Media Analytics

  Do you have videos or audio on your website, or in an app ? Media Analytics gives you powerful insights into how your audience watches your videos and listens to your audio, to ultimately maximize your success.

  Learn all about your audience. Which media your users are playing, for how long, how often, and where they dropped off ? Where are your users located around the world ? Who your audience are and what did people do before and after watching a video or listening to audio ? Many of the reports are also available in Real time, so you can gain insights and react quickly.

  Get it now on the Marketplace

  Learn more here :

  • Media Analytics (website).
  • List of all features on the Marketplace : Media Analytics plugin.
  • Screenshots for Media Analytics.

  • The Media Analytics User Guide and the Media Analytics FAQ cover on how to get the most out of this plugin. The Media Analytics developer guides help you setting up the tracking of your video and audio.

  • 
    Powerful Video Analytics and Audio Analytics for Piwik
    (blog post).

  

  3. Activity log

  Keep an eye on everything that is happening on your Piwik platform with the Activity Log plugin.

  The activity log, also known as audit log or audit trail, improves your Piwik’s security and diagnostic by showing a chronological set of entries that provides documentary evidence of activities that happened in your Piwik. It allows Piwik Super Users to quickly review the actions performed by members of your organization or clients, and also lets every user review details of their own actions.

  Get it now on the Marketplace

  Learn more in the Activity Log FAQ or see a list of all the features on the Marketplace : Activity Log plugin.

  

  The Piwik Marketplace guarantees

  Purchasing on the Piwik Marketplace is easy and safe. Check out our guarantees :

  • Marketplace refund policy : 14 Day Money Back Guarantee.
  • Safe & Secure Payments.
  • 1-click Installation & Update.

  Why premium plugins ?

  Researching, building, documenting, testing and maintaining quality products take years of experience and months of work. When you purchase a premium plugin from the Marketplace, you get a fully working product, with free updates for the duration of the license and you stay in full control of your analytics data. When purchasing premium plugins you also directly help the Piwik core engineers to continue to grow and innovate ! That’s because a % of earnings on premium plugin license sales directly fund new Piwik versions and more amazing features. Learn more in the FAQ : What are premium plugins ?.

  About InnoCraft

  These first three premium plugins have been designed and built with love by InnoCraft. InnoCraft is a new company founded by the creator of Piwik along with the lead engineers of Piwik based in Wellington, New Zealand. At InnoCraft, product experts, designers and engineers are passionate about crafting high quality and innovative products to help grow your business and to maximize your success.

  Learn more on the company website : www.innocraft.com

  To stay updated on their releases, follow InnoCraftHQ on Twitter or Like InnoCraft on Facebook.

  

  Is the Piwik Marketplace open to all ?

  Yes, our marketplace allows other companies and developers to sell their plugins to all Piwik Analytics users. If you are a developer or a company interested in selling your plugin(s) on our Marketplace please contact us. As a developer selling plugins, you will get paid every month for your earnings, and you will be able to see detailed reports about your sales, upload new plugin updates, respond to pre-sales enquiries, etc.

  Resources

  Learn more :

  • The Piwik.org Privacy Policy has been updated (a new “Scope” and “Contact us” sections).
  • New Terms and Conditions for the Piwik Marketplace (plugins.piwik.org).
  • New Piwik Marketplace FAQs.
  • What are premium plugins and how do they differ from free plugins ?.

  We are looking forward to your continued support with the Piwik project as we expand and offer you more ways to maximize your success.

  Please contact the Marketplace team with any questions or feedback.

  Wishing you a warm : Happy Analytics !